/** * \file psa/crypto_se_driver.h * \brief PSA external cryptoprocessor driver module * * This header declares types and function signatures for cryptography * drivers that access key material via opaque references. * This is meant for cryptoprocessors that have a separate key storage from the * space in which the PSA Crypto implementation runs, typically secure * elements (SEs). * * This file is part of the PSA Crypto Driver Model, containing functions for * driver developers to implement to enable hardware to be called in a * standardized way by a PSA Cryptographic API implementation. The functions * comprising the driver model, which driver authors implement, are not * intended to be called by application developers. */ /* * Copyright (C) 2018, ARM Limited, All Rights Reserved * SPDX-License-Identifier: Apache-2.0 * * Licensed under the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef PSA_CRYPTO_SE_DRIVER_H #define PSA_CRYPTO_SE_DRIVER_H #include "crypto_driver_common.h" #ifdef __cplusplus extern "C" { #endif /** An internal designation of a key slot between the core part of the * PSA Crypto implementation and the driver. The meaning of this value * is driver-dependent. */ typedef uint32_t psa_key_slot_number_t; // Change this to psa_key_slot_t after psa_key_slot_t is removed from Mbed crypto /** \defgroup se_mac Secure Element Message Authentication Codes * Generation and authentication of Message Authentication Codes (MACs) using * a secure element can be done either as a single function call (via the * `psa_drv_se_mac_generate_t` or `psa_drv_se_mac_verify_t` functions), or in * parts using the following sequence: * - `psa_drv_se_mac_setup_t` * - `psa_drv_se_mac_update_t` * - `psa_drv_se_mac_update_t` * - ... * - `psa_drv_se_mac_finish_t` or `psa_drv_se_mac_finish_verify_t` * * If a previously started secure element MAC operation needs to be terminated, * it should be done so by the `psa_drv_se_mac_abort_t`. Failure to do so may * result in allocated resources not being freed or in other undefined * behavior. */ /**@{*/ /** \brief A function that starts a secure element MAC operation for a PSA * Crypto Driver implementation * * \param[in,out] p_context A structure that will contain the * hardware-specific MAC context * \param[in] key_slot The slot of the key to be used for the * operation * \param[in] algorithm The algorithm to be used to underly the MAC * operation * * \retval PSA_SUCCESS * Success. */ typedef psa_status_t (*psa_drv_se_mac_setup_t)(void *p_context, psa_key_slot_number_t key_slot, psa_algorithm_t algorithm); /** \brief A function that continues a previously started secure element MAC * operation * * \param[in,out] p_context A hardware-specific structure for the * previously-established MAC operation to be * updated * \param[in] p_input A buffer containing the message to be appended * to the MAC operation * \param[in] input_length The size in bytes of the input message buffer */ typedef psa_status_t (*psa_drv_se_mac_update_t)(void *p_context, const uint8_t *p_input, size_t input_length); /** \brief a function that completes a previously started secure element MAC * operation by returning the resulting MAC. * * \param[in,out] p_context A hardware-specific structure for the * previously started MAC operation to be * finished * \param[out] p_mac A buffer where the generated MAC will be * placed * \param[in] mac_size The size in bytes of the buffer that has been * allocated for the `output` buffer * \param[out] p_mac_length After completion, will contain the number of * bytes placed in the `p_mac` buffer * * \retval PSA_SUCCESS * Success. */ typedef psa_status_t (*psa_drv_se_mac_finish_t)(void *p_context, uint8_t *p_mac, size_t mac_size, size_t *p_mac_length); /** \brief A function that completes a previously started secure element MAC * operation by comparing the resulting MAC against a provided value * * \param[in,out] p_context A hardware-specific structure for the previously * started MAC operation to be fiinished * \param[in] p_mac The MAC value against which the resulting MAC will * be compared against * \param[in] mac_length The size in bytes of the value stored in `p_mac` * * \retval PSA_SUCCESS * The operation completed successfully and the MACs matched each * other * \retval PSA_ERROR_INVALID_SIGNATURE * The operation completed successfully, but the calculated MAC did * not match the provided MAC */ typedef psa_status_t (*psa_drv_se_mac_finish_verify_t)(void *p_context, const uint8_t *p_mac, size_t mac_length); /** \brief A function that aborts a previous started secure element MAC * operation * * \param[in,out] p_context A hardware-specific structure for the previously * started MAC operation to be aborted */ typedef psa_status_t (*psa_drv_se_mac_abort_t)(void *p_context); /** \brief A function that performs a secure element MAC operation in one * command and returns the calculated MAC * * \param[in] p_input A buffer containing the message to be MACed * \param[in] input_length The size in bytes of `p_input` * \param[in] key_slot The slot of the key to be used * \param[in] alg The algorithm to be used to underlie the MAC * operation * \param[out] p_mac A buffer where the generated MAC will be * placed * \param[in] mac_size The size in bytes of the `p_mac` buffer * \param[out] p_mac_length After completion, will contain the number of * bytes placed in the `output` buffer * * \retval PSA_SUCCESS * Success. */ typedef psa_status_t (*psa_drv_se_mac_generate_t)(const uint8_t *p_input, size_t input_length, psa_key_slot_number_t key_slot, psa_algorithm_t alg, uint8_t *p_mac, size_t mac_size, size_t *p_mac_length); /** \brief A function that performs a secure element MAC operation in one * command and compares the resulting MAC against a provided value * * \param[in] p_input A buffer containing the message to be MACed * \param[in] input_length The size in bytes of `input` * \param[in] key_slot The slot of the key to be used * \param[in] alg The algorithm to be used to underlie the MAC * operation * \param[in] p_mac The MAC value against which the resulting MAC will * be compared against * \param[in] mac_length The size in bytes of `mac` * * \retval PSA_SUCCESS * The operation completed successfully and the MACs matched each * other * \retval PSA_ERROR_INVALID_SIGNATURE * The operation completed successfully, but the calculated MAC did * not match the provided MAC */ typedef psa_status_t (*psa_drv_se_mac_verify_t)(const uint8_t *p_input, size_t input_length, psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_mac, size_t mac_length); /** \brief A struct containing all of the function pointers needed to * perform secure element MAC operations * * PSA Crypto API implementations should populate the table as appropriate * upon startup. * * If one of the functions is not implemented (such as * `psa_drv_se_mac_generate_t`), it should be set to NULL. * * Driver implementers should ensure that they implement all of the functions * that make sense for their hardware, and that they provide a full solution * (for example, if they support `p_setup`, they should also support * `p_update` and at least one of `p_finish` or `p_finish_verify`). * */ typedef struct { /**The size in bytes of the hardware-specific secure element MAC context * structure */ size_t context_size; /** Function that performs a MAC setup operation */ psa_drv_se_mac_setup_t p_setup; /** Function that performs a MAC update operation */ psa_drv_se_mac_update_t p_update; /** Function that completes a MAC operation */ psa_drv_se_mac_finish_t p_finish; /** Function that completes a MAC operation with a verify check */ psa_drv_se_mac_finish_verify_t p_finish_verify; /** Function that aborts a previoustly started MAC operation */ psa_drv_se_mac_abort_t p_abort; /** Function that performs a MAC operation in one call */ psa_drv_se_mac_generate_t p_mac; /** Function that performs a MAC and verify operation in one call */ psa_drv_se_mac_verify_t p_mac_verify; } psa_drv_se_mac_t; /**@}*/ /** \defgroup se_cipher Secure Element Symmetric Ciphers * * Encryption and Decryption using secure element keys in block modes other * than ECB must be done in multiple parts, using the following flow: * - `psa_drv_se_cipher_setup_t` * - `psa_drv_se_cipher_set_iv_t` (optional depending upon block mode) * - `psa_drv_se_cipher_update_t` * - `psa_drv_se_cipher_update_t` * - ... * - `psa_drv_se_cipher_finish_t` * * If a previously started secure element Cipher operation needs to be * terminated, it should be done so by the `psa_drv_se_cipher_abort_t`. Failure * to do so may result in allocated resources not being freed or in other * undefined behavior. * * In situations where a PSA Cryptographic API implementation is using a block * mode not-supported by the underlying hardware or driver, it can construct * the block mode itself, while calling the `psa_drv_se_cipher_ecb_t` function * for the cipher operations. */ /**@{*/ /** \brief A function that provides the cipher setup function for a * secure element driver * * \param[in,out] p_context A structure that will contain the * hardware-specific cipher context. * \param[in] key_slot The slot of the key to be used for the * operation * \param[in] algorithm The algorithm to be used in the cipher * operation * \param[in] direction Indicates whether the operation is an encrypt * or decrypt * * \retval PSA_SUCCESS * \retval PSA_ERROR_NOT_SUPPORTED */ typedef psa_status_t (*psa_drv_se_cipher_setup_t)(void *p_context, psa_key_slot_number_t key_slot, psa_algorithm_t algorithm, psa_encrypt_or_decrypt_t direction); /** \brief A function that sets the initialization vector (if * necessary) for an secure element cipher operation * * Rationale: The `psa_se_cipher_*` operation in the PSA Cryptographic API has * two IV functions: one to set the IV, and one to generate it internally. The * generate function is not necessary for the drivers to implement as the PSA * Crypto implementation can do the generation using its RNG features. * * \param[in,out] p_context A structure that contains the previously set up * hardware-specific cipher context * \param[in] p_iv A buffer containing the initialization vector * \param[in] iv_length The size (in bytes) of the `p_iv` buffer * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_cipher_set_iv_t)(void *p_context, const uint8_t *p_iv, size_t iv_length); /** \brief A function that continues a previously started secure element cipher * operation * * \param[in,out] p_context A hardware-specific structure for the * previously started cipher operation * \param[in] p_input A buffer containing the data to be * encrypted/decrypted * \param[in] input_size The size in bytes of the buffer pointed to * by `p_input` * \param[out] p_output The caller-allocated buffer where the * output will be placed * \param[in] output_size The allocated size in bytes of the * `p_output` buffer * \param[out] p_output_length After completion, will contain the number * of bytes placed in the `p_output` buffer * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_cipher_update_t)(void *p_context, const uint8_t *p_input, size_t input_size, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** \brief A function that completes a previously started secure element cipher * operation * * \param[in,out] p_context A hardware-specific structure for the * previously started cipher operation * \param[out] p_output The caller-allocated buffer where the output * will be placed * \param[in] output_size The allocated size in bytes of the `p_output` * buffer * \param[out] p_output_length After completion, will contain the number of * bytes placed in the `p_output` buffer * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_cipher_finish_t)(void *p_context, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** \brief A function that aborts a previously started secure element cipher * operation * * \param[in,out] p_context A hardware-specific structure for the * previously started cipher operation */ typedef psa_status_t (*psa_drv_se_cipher_abort_t)(void *p_context); /** \brief A function that performs the ECB block mode for secure element * cipher operations * * Note: this function should only be used with implementations that do not * provide a needed higher-level operation. * * \param[in] key_slot The slot of the key to be used for the operation * \param[in] algorithm The algorithm to be used in the cipher operation * \param[in] direction Indicates whether the operation is an encrypt or * decrypt * \param[in] p_input A buffer containing the data to be * encrypted/decrypted * \param[in] input_size The size in bytes of the buffer pointed to by * `p_input` * \param[out] p_output The caller-allocated buffer where the output will * be placed * \param[in] output_size The allocated size in bytes of the `p_output` * buffer * * \retval PSA_SUCCESS * \retval PSA_ERROR_NOT_SUPPORTED */ typedef psa_status_t (*psa_drv_se_cipher_ecb_t)(psa_key_slot_number_t key_slot, psa_algorithm_t algorithm, psa_encrypt_or_decrypt_t direction, const uint8_t *p_input, size_t input_size, uint8_t *p_output, size_t output_size); /** * \brief A struct containing all of the function pointers needed to implement * cipher operations using secure elements. * * PSA Crypto API implementations should populate instances of the table as * appropriate upon startup or at build time. * * If one of the functions is not implemented (such as * `psa_drv_se_cipher_ecb_t`), it should be set to NULL. */ typedef struct { /** The size in bytes of the hardware-specific secure element cipher * context structure */ size_t context_size; /** Function that performs a cipher setup operation */ psa_drv_se_cipher_setup_t p_setup; /** Function that sets a cipher IV (if necessary) */ psa_drv_se_cipher_set_iv_t p_set_iv; /** Function that performs a cipher update operation */ psa_drv_se_cipher_update_t p_update; /** Function that completes a cipher operation */ psa_drv_se_cipher_finish_t p_finish; /** Function that aborts a cipher operation */ psa_drv_se_cipher_abort_t p_abort; /** Function that performs ECB mode for a cipher operation * (Danger: ECB mode should not be used directly by clients of the PSA * Crypto Client API) */ psa_drv_se_cipher_ecb_t p_ecb; } psa_drv_se_cipher_t; /**@}*/ /** \defgroup se_asymmetric Secure Element Asymmetric Cryptography * * Since the amount of data that can (or should) be encrypted or signed using * asymmetric keys is limited by the key size, asymmetric key operations using * keys in a secure element must be done in single function calls. */ /**@{*/ /** * \brief A function that signs a hash or short message with a private key in * a secure element * * \param[in] key_slot Key slot of an asymmetric key pair * \param[in] alg A signature algorithm that is compatible * with the type of `key` * \param[in] p_hash The hash to sign * \param[in] hash_length Size of the `p_hash` buffer in bytes * \param[out] p_signature Buffer where the signature is to be written * \param[in] signature_size Size of the `p_signature` buffer in bytes * \param[out] p_signature_length On success, the number of bytes * that make up the returned signature value * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_asymmetric_sign_t)(psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_hash, size_t hash_length, uint8_t *p_signature, size_t signature_size, size_t *p_signature_length); /** * \brief A function that verifies the signature a hash or short message using * an asymmetric public key in a secure element * * \param[in] key_slot Key slot of a public key or an asymmetric key * pair * \param[in] alg A signature algorithm that is compatible with * the type of `key` * \param[in] p_hash The hash whose signature is to be verified * \param[in] hash_length Size of the `p_hash` buffer in bytes * \param[in] p_signature Buffer containing the signature to verify * \param[in] signature_length Size of the `p_signature` buffer in bytes * * \retval PSA_SUCCESS * The signature is valid. */ typedef psa_status_t (*psa_drv_se_asymmetric_verify_t)(psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_hash, size_t hash_length, const uint8_t *p_signature, size_t signature_length); /** * \brief A function that encrypts a short message with an asymmetric public * key in a secure element * * \param[in] key_slot Key slot of a public key or an asymmetric key * pair * \param[in] alg An asymmetric encryption algorithm that is * compatible with the type of `key` * \param[in] p_input The message to encrypt * \param[in] input_length Size of the `p_input` buffer in bytes * \param[in] p_salt A salt or label, if supported by the * encryption algorithm * If the algorithm does not support a * salt, pass `NULL`. * If the algorithm supports an optional * salt and you do not want to pass a salt, * pass `NULL`. * For #PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is * supported. * \param[in] salt_length Size of the `p_salt` buffer in bytes * If `p_salt` is `NULL`, pass 0. * \param[out] p_output Buffer where the encrypted message is to * be written * \param[in] output_size Size of the `p_output` buffer in bytes * \param[out] p_output_length On success, the number of bytes that make up * the returned output * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_asymmetric_encrypt_t)(psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_input, size_t input_length, const uint8_t *p_salt, size_t salt_length, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** * \brief A function that decrypts a short message with an asymmetric private * key in a secure element. * * \param[in] key_slot Key slot of an asymmetric key pair * \param[in] alg An asymmetric encryption algorithm that is * compatible with the type of `key` * \param[in] p_input The message to decrypt * \param[in] input_length Size of the `p_input` buffer in bytes * \param[in] p_salt A salt or label, if supported by the * encryption algorithm * If the algorithm does not support a * salt, pass `NULL`. * If the algorithm supports an optional * salt and you do not want to pass a salt, * pass `NULL`. * For #PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is * supported. * \param[in] salt_length Size of the `p_salt` buffer in bytes * If `p_salt` is `NULL`, pass 0. * \param[out] p_output Buffer where the decrypted message is to * be written * \param[in] output_size Size of the `p_output` buffer in bytes * \param[out] p_output_length On success, the number of bytes * that make up the returned output * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_asymmetric_decrypt_t)(psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_input, size_t input_length, const uint8_t *p_salt, size_t salt_length, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** * \brief A struct containing all of the function pointers needed to implement * asymmetric cryptographic operations using secure elements. * * PSA Crypto API implementations should populate instances of the table as * appropriate upon startup or at build time. * * If one of the functions is not implemented, it should be set to NULL. */ typedef struct { /** Function that performs an asymmetric sign operation */ psa_drv_se_asymmetric_sign_t p_sign; /** Function that performs an asymmetric verify operation */ psa_drv_se_asymmetric_verify_t p_verify; /** Function that performs an asymmetric encrypt operation */ psa_drv_se_asymmetric_encrypt_t p_encrypt; /** Function that performs an asymmetric decrypt operation */ psa_drv_se_asymmetric_decrypt_t p_decrypt; } psa_drv_se_asymmetric_t; /**@}*/ /** \defgroup se_aead Secure Element Authenticated Encryption with Additional Data * Authenticated Encryption with Additional Data (AEAD) operations with secure * elements must be done in one function call. While this creates a burden for * implementers as there must be sufficient space in memory for the entire * message, it prevents decrypted data from being made available before the * authentication operation is complete and the data is known to be authentic. */ /**@{*/ /** \brief A function that performs a secure element authenticated encryption * operation * * \param[in] key_slot Slot containing the key to use. * \param[in] algorithm The AEAD algorithm to compute * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(`alg`) is true) * \param[in] p_nonce Nonce or IV to use * \param[in] nonce_length Size of the `p_nonce` buffer in bytes * \param[in] p_additional_data Additional data that will be * authenticated but not encrypted * \param[in] additional_data_length Size of `p_additional_data` in bytes * \param[in] p_plaintext Data that will be authenticated and * encrypted * \param[in] plaintext_length Size of `p_plaintext` in bytes * \param[out] p_ciphertext Output buffer for the authenticated and * encrypted data. The additional data is * not part of this output. For algorithms * where the encrypted data and the * authentication tag are defined as * separate outputs, the authentication * tag is appended to the encrypted data. * \param[in] ciphertext_size Size of the `p_ciphertext` buffer in * bytes * \param[out] p_ciphertext_length On success, the size of the output in * the `p_ciphertext` buffer * * \retval #PSA_SUCCESS * Success. */ typedef psa_status_t (*psa_drv_se_aead_encrypt_t)(psa_key_slot_number_t key_slot, psa_algorithm_t algorithm, const uint8_t *p_nonce, size_t nonce_length, const uint8_t *p_additional_data, size_t additional_data_length, const uint8_t *p_plaintext, size_t plaintext_length, uint8_t *p_ciphertext, size_t ciphertext_size, size_t *p_ciphertext_length); /** A function that peforms a secure element authenticated decryption operation * * \param[in] key_slot Slot containing the key to use * \param[in] algorithm The AEAD algorithm to compute * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(`alg`) is true) * \param[in] p_nonce Nonce or IV to use * \param[in] nonce_length Size of the `p_nonce` buffer in bytes * \param[in] p_additional_data Additional data that has been * authenticated but not encrypted * \param[in] additional_data_length Size of `p_additional_data` in bytes * \param[in] p_ciphertext Data that has been authenticated and * encrypted. * For algorithms where the encrypted data * and the authentication tag are defined * as separate inputs, the buffer must * contain the encrypted data followed by * the authentication tag. * \param[in] ciphertext_length Size of `p_ciphertext` in bytes * \param[out] p_plaintext Output buffer for the decrypted data * \param[in] plaintext_size Size of the `p_plaintext` buffer in * bytes * \param[out] p_plaintext_length On success, the size of the output in * the `p_plaintext` buffer * * \retval #PSA_SUCCESS * Success. */ typedef psa_status_t (*psa_drv_se_aead_decrypt_t)(psa_key_slot_number_t key_slot, psa_algorithm_t algorithm, const uint8_t *p_nonce, size_t nonce_length, const uint8_t *p_additional_data, size_t additional_data_length, const uint8_t *p_ciphertext, size_t ciphertext_length, uint8_t *p_plaintext, size_t plaintext_size, size_t *p_plaintext_length); /** * \brief A struct containing all of the function pointers needed to implement * secure element Authenticated Encryption with Additional Data operations * * PSA Crypto API implementations should populate instances of the table as * appropriate upon startup. * * If one of the functions is not implemented, it should be set to NULL. */ typedef struct { /** Function that performs the AEAD encrypt operation */ psa_drv_se_aead_encrypt_t p_encrypt; /** Function that performs the AEAD decrypt operation */ psa_drv_se_aead_decrypt_t p_decrypt; } psa_drv_se_aead_t; /**@}*/ /** \defgroup se_key_management Secure Element Key Management * Currently, key management is limited to importing keys in the clear, * destroying keys, and exporting keys in the clear. * Whether a key may be exported is determined by the key policies in place * on the key slot. */ /**@{*/ /** \brief A function that imports a key into a secure element in binary format * * This function can support any output from psa_export_key(). Refer to the * documentation of psa_export_key() for the format for each key type. * * \param[in] key_slot Slot where the key will be stored * This must be a valid slot for a key of the chosen * type. It must be unoccupied. * \param[in] lifetime The required lifetime of the key storage * \param[in] type Key type (a \c PSA_KEY_TYPE_XXX value) * \param[in] algorithm Key algorithm (a \c PSA_ALG_XXX value) * \param[in] usage The allowed uses of the key * \param[in] p_data Buffer containing the key data * \param[in] data_length Size of the `data` buffer in bytes * * \retval #PSA_SUCCESS * Success. */ typedef psa_status_t (*psa_drv_se_import_key_t)(psa_key_slot_number_t key_slot, psa_key_lifetime_t lifetime, psa_key_type_t type, psa_algorithm_t algorithm, psa_key_usage_t usage, const uint8_t *p_data, size_t data_length); /** * \brief A function that destroys a secure element key and restore the slot to * its default state * * This function destroys the content of the key from a secure element. * Implementations shall make a best effort to ensure that any previous content * of the slot is unrecoverable. * * This function returns the specified slot to its default state. * * \param[in] key_slot The key slot to erase. * * \retval #PSA_SUCCESS * The slot's content, if any, has been erased. */ typedef psa_status_t (*psa_drv_se_destroy_key_t)(psa_key_slot_number_t key); /** * \brief A function that exports a secure element key in binary format * * The output of this function can be passed to psa_import_key() to * create an equivalent object. * * If a key is created with `psa_import_key()` and then exported with * this function, it is not guaranteed that the resulting data is * identical: the implementation may choose a different representation * of the same key if the format permits it. * * This function should generate output in the same format that * `psa_export_key()` does. Refer to the * documentation of `psa_export_key()` for the format for each key type. * * \param[in] key Slot whose content is to be exported. This must * be an occupied key slot. * \param[out] p_data Buffer where the key data is to be written. * \param[in] data_size Size of the `p_data` buffer in bytes. * \param[out] p_data_length On success, the number of bytes * that make up the key data. * * \retval #PSA_SUCCESS * \retval #PSA_ERROR_DOES_NOT_EXIST * \retval #PSA_ERROR_NOT_PERMITTED * \retval #PSA_ERROR_NOT_SUPPORTED * \retval #PSA_ERROR_COMMUNICATION_FAILURE * \retval #PSA_ERROR_HARDWARE_FAILURE * \retval #PSA_ERROR_CORRUPTION_DETECTED */ typedef psa_status_t (*psa_drv_se_export_key_t)(psa_key_slot_number_t key, uint8_t *p_data, size_t data_size, size_t *p_data_length); /** * \brief A function that generates a symmetric or asymmetric key on a secure * element * * If \p type is asymmetric (`#PSA_KEY_TYPE_IS_ASYMMETRIC(\p type) == 1`), * the public component of the generated key will be placed in `p_pubkey_out`. * The format of the public key information will match the format specified for * the psa_export_key() function for the key type. * * \param[in] key_slot Slot where the generated key will be placed * \param[in] type The type of the key to be generated * \param[in] usage The prescribed usage of the generated key * Note: Not all Secure Elements support the same * restrictions that PSA Crypto does (and vice versa). * Driver developers should endeavor to match the * usages as close as possible. * \param[in] bits The size in bits of the key to be generated. * \param[in] extra Extra parameters for key generation. The * interpretation of this parameter should match the * interpretation in the `extra` parameter is the * `psa_generate_key` function * \param[in] extra_size The size in bytes of the \p extra buffer * \param[out] p_pubkey_out The buffer where the public key information will * be placed * \param[in] pubkey_out_size The size in bytes of the `p_pubkey_out` buffer * \param[out] p_pubkey_length Upon successful completion, will contain the * size of the data placed in `p_pubkey_out`. */ typedef psa_status_t (*psa_drv_se_generate_key_t)(psa_key_slot_number_t key_slot, psa_key_type_t type, psa_key_usage_t usage, size_t bits, const void *extra, size_t extra_size, uint8_t *p_pubkey_out, size_t pubkey_out_size, size_t *p_pubkey_length); /** * \brief A struct containing all of the function pointers needed to for secure * element key management * * PSA Crypto API implementations should populate instances of the table as * appropriate upon startup or at build time. * * If one of the functions is not implemented, it should be set to NULL. */ typedef struct { /** Function that performs a key import operation */ psa_drv_se_import_key_t p_import; /** Function that performs a generation */ psa_drv_se_generate_key_t p_generate; /** Function that performs a key destroy operation */ psa_drv_se_destroy_key_t p_destroy; /** Function that performs a key export operation */ psa_drv_se_export_key_t p_export; } psa_drv_se_key_management_t; /**@}*/ /** \defgroup driver_derivation Secure Element Key Derivation and Agreement * Key derivation is the process of generating new key material using an * existing key and additional parameters, iterating through a basic * cryptographic function, such as a hash. * Key agreement is a part of cryptographic protocols that allows two parties * to agree on the same key value, but starting from different original key * material. * The flows are similar, and the PSA Crypto Driver Model uses the same functions * for both of the flows. * * There are two different final functions for the flows, * `psa_drv_se_key_derivation_derive` and `psa_drv_se_key_derivation_export`. * `psa_drv_se_key_derivation_derive` is used when the key material should be * placed in a slot on the hardware and not exposed to the caller. * `psa_drv_se_key_derivation_export` is used when the key material should be * returned to the PSA Cryptographic API implementation. * * Different key derivation algorithms require a different number of inputs. * Instead of having an API that takes as input variable length arrays, which * can be problemmatic to manage on embedded platforms, the inputs are passed * to the driver via a function, `psa_drv_se_key_derivation_collateral`, that * is called multiple times with different `collateral_id`s. Thus, for a key * derivation algorithm that required 3 paramter inputs, the flow would look * something like: * ~~~~~~~~~~~~~{.c} * psa_drv_se_key_derivation_setup(kdf_algorithm, source_key, dest_key_size_bytes); * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_0, * p_collateral_0, * collateral_0_size); * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_1, * p_collateral_1, * collateral_1_size); * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_2, * p_collateral_2, * collateral_2_size); * psa_drv_se_key_derivation_derive(); * ~~~~~~~~~~~~~ * * key agreement example: * ~~~~~~~~~~~~~{.c} * psa_drv_se_key_derivation_setup(alg, source_key. dest_key_size_bytes); * psa_drv_se_key_derivation_collateral(DHE_PUBKEY, p_pubkey, pubkey_size); * psa_drv_se_key_derivation_export(p_session_key, * session_key_size, * &session_key_length); * ~~~~~~~~~~~~~ */ /**@{*/ /** \brief A function that Sets up a secure element key derivation operation by * specifying the algorithm and the source key sot * * \param[in,out] p_context A hardware-specific structure containing any * context information for the implementation * \param[in] kdf_alg The algorithm to be used for the key derivation * \param[in] souce_key The key to be used as the source material for the * key derivation * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_key_derivation_setup_t)(void *p_context, psa_algorithm_t kdf_alg, psa_key_slot_number_t source_key); /** \brief A function that provides collateral (parameters) needed for a secure * element key derivation or key agreement operation * * Since many key derivation algorithms require multiple parameters, it is * expeced that this function may be called multiple times for the same * operation, each with a different algorithm-specific `collateral_id` * * \param[in,out] p_context A hardware-specific structure containing any * context information for the implementation * \param[in] collateral_id An ID for the collateral being provided * \param[in] p_collateral A buffer containing the collateral data * \param[in] collateral_size The size in bytes of the collateral * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_key_derivation_collateral_t)(void *p_context, uint32_t collateral_id, const uint8_t *p_collateral, size_t collateral_size); /** \brief A function that performs the final secure element key derivation * step and place the generated key material in a slot * * \param[in,out] p_context A hardware-specific structure containing any * context information for the implementation * \param[in] dest_key The slot where the generated key material * should be placed * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_key_derivation_derive_t)(void *p_context, psa_key_slot_number_t dest_key); /** \brief A function that performs the final step of a secure element key * agreement and place the generated key material in a buffer * * \param[out] p_output Buffer in which to place the generated key * material * \param[in] output_size The size in bytes of `p_output` * \param[out] p_output_length Upon success, contains the number of bytes of * key material placed in `p_output` * * \retval PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_key_derivation_export_t)(void *p_context, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** * \brief A struct containing all of the function pointers needed to for secure * element key derivation and agreement * * PSA Crypto API implementations should populate instances of the table as * appropriate upon startup. * * If one of the functions is not implemented, it should be set to NULL. */ typedef struct { /** The driver-specific size of the key derivation context */ size_t context_size; /** Function that performs a key derivation setup */ psa_drv_se_key_derivation_setup_t p_setup; /** Function that sets key derivation collateral */ psa_drv_se_key_derivation_collateral_t p_collateral; /** Function that performs a final key derivation step */ psa_drv_se_key_derivation_derive_t p_derive; /** Function that perforsm a final key derivation or agreement and * exports the key */ psa_drv_se_key_derivation_export_t p_export; } psa_drv_se_key_derivation_t; /**@}*/ #ifdef __cplusplus } #endif #endif /* PSA_CRYPTO_SE_DRIVER_H */